using a 3D printed model, you can make many silicone models with a fast curing silicone  and make hundreds of replicas in short time using a fast curing poliurethane resine

Files for the model and guide are in the link

Casting silicone on a 3D printed model with printed containing walls

With a coumple of models, you can make many molds and many parts quickly

In this case, I used a guide to incorporated a perforated sheet of PVC directly into the model, makeing it sturdier and safer for the user.